Semiconductor device, apparatus and method for manufacturing the same

ABSTRACT

An apparatus for manufacturing a semiconductor device is disclosed which comprises a chamber which holds a to-be-processed substrate having a film containing at least one kind of metal element which will become a component of a volatile metal compound, a heater which heats the substrate held in the chamber, and an adsorbent which is provided in the chamber and which adsorbs the volatile metal compound generated from the film by heating the substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims the benefit of priorityfrom the prior Japanese Patent Application No. 2003-032426, filed Feb.10, 2003, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a thermal treatment process inthe manufacturing process of semiconductor devices. In particular, thepresent invention relates to apparatus and method for manufacturing asemiconductor device, which are applied to a heating process whenforming electrodes of FeRAM capacitor devices using metal oxide.

[0004] 2. Description of the Related Art

[0005] For instance, in one kind of semiconductor devices, that is,FeRAM (Ferroelectric Random Access Read Memory), the insulating film ofcapacitor device is formed using oxide ferroelectric material film inorder to achieve the number of 10¹² rewritable times or more. Forexample, PZT (Pb—Zr—Ti—O) is given as the above oxide ferroelectricmaterial film. In addition, in the FeRAM, the electrode of the capacitordevice is formed using metal oxide conductor in order to prevent thedegradation of electrical characteristics of the oxide ferroelectricmaterial film. For example, SRO (SrRuO₃) is given as the above metaloxide conductor. The SRO is crystallized, thereby having conductivity.In order to crystallize the SRO, heat treatment process is required whenforming SRO electrode.

[0006] However, one component of the SRO, that is, Ru is easy togenerate a volatile substance, that is, RuO₄ in the heat treatmentprocess of the SRO electrode. The generated RuO₄ is decomposed afteradhering to the surface of the SRO electrode (SRO film); as a result,RuO_(X) crystal particles (abnormal particles) are generated on thesurface of the SRO film, as shown in FIG. 4. The above RuO_(X) crystalparticles have a diameter of about 0.5 μm or more. For this reason, itis almost impossible to remove the RuO_(X) crystal particles from theSRO electrode by after-cleaning. As a result, the RuO_(X) crystalparticles on the SRO electrode has a possibility of causing theoperation failure of the capacitor. In addition, the RuO_(X) crystalparticles have a possibility of reducing semiconductor deviceperformance, quality and reliability. Consequently, the RuO_(X) crystalparticles are a factor of reducing semiconductor device yield, and thus,increasing the manufacturing cost of semiconductor devices.

BRIEF SUMMARY OF THE INVENTION

[0007] According to an aspect of the present invention, there isprovided an apparatus for manufacturing a semiconductor device,comprising: a chamber which holds a to-be-processed substrate having afilm containing at least one kind of metal element which will become acomponent of a volatile metal compound; a heater which heats thesubstrate held in the chamber; and an adsorbent which is provided in thechamber and which adsorbs the volatile metal compound generated from thefilm by heating the substrate.

[0008] According to another aspect of the present invention, there isprovided a method of manufacturing a semiconductor device, comprising:providing an adsorbent in a chamber holding a to-be-processed substrateand heating the substrate, the substrate having a film containing atleast one kind of metal element which will become a component of avolatile metal compound; and causing the adsorbent to adsorb thevolatile metal compound generated from the film by heating thesubstrate.

[0009] According to a further aspect of the present invention, there isprovided a semiconductor device comprising: a semiconductor substratehaving a film containing at least one kind of metal element which willbecome a component of a volatile metal compound, the semiconductorsubstrate having being heated by an apparatus for manufacturing asemiconductor device, the apparatus comprising: a chamber which holdsthe semiconductor substrate; a heater which heats the semiconductorsubstrate held in the chamber; and an adsorbent which is provided in thechamber and which adsorbs the volatile metal compound generated from thefilm by heating the semiconductor substrate.

[0010] According to yet another aspect of the present invention, thereis provided a semiconductor device comprising: a semiconductor substratehaving a film containing at least one kind of metal element which willbecome a component of a volatile metal compound, the semiconductorsubstrate having being heated by a method of manufacturing asemiconductor device, the method comprising: providing an adsorbent in achamber holding the semiconductor substrate and heating thesemiconductor substrate; and causing the adsorbent to adsorb thevolatile metal compound generated from the film by heating thesemiconductor substrate.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0011]FIG. 1 is a cross-sectional view showing an apparatus formanufacturing a semiconductor device according to one embodiment of thepresent invention;

[0012]FIG. 2A is a cross-sectional view showing a process in a method ofmanufacturing a semiconductor device according to one embodiment of thepresent invention;

[0013]FIG. 2B is a cross-sectional view showing a process in the methodof manufacturing a semiconductor device according to one embodiment ofthe present invention;

[0014]FIG. 2C is a cross-sectional view showing a process in the methodof manufacturing a semiconductor device according to one embodiment ofthe present invention;

[0015]FIG. 3 is a diagram plotting the relationship between the numberof particles generated when heating wafer and the number of processingwafers; and

[0016]FIG. 4 is a photograph showing abnormal particle generated whenheating wafer by a method of manufacturing a semiconductor deviceaccording to the conventional technique.

DETAILED DESCRIPTION OF THE INVENTION

[0017] Embodiments of the present invention will be described below withreference to the accompanying drawings.

[0018] First, an apparatus for manufacturing a semiconductor deviceaccording to one embodiment will be described referring to FIG. 1. FIG.1 is a cross-sectional view showing an apparatus for manufacturing asemiconductor device according to one embodiment of the presentinvention.

[0019] As shown in FIG. 1, the apparatus for manufacturing asemiconductor device according to the embodiment (hereinafter, referredsimply to as “apparatus”) 1 includes a chamber 2, a heater 3 andadsorbent 4. The apparatus 1 is a so-called thermal treatment apparatus(annealer).

[0020] The chamber 2 houses a processing substrate (wafer) 5 therein.The wafer 5 includes a film 34 containing a metal element, which is acomponent of a volatile metal compound. The wafer 5 is housed in thechamber 2, and thereafter, heated. The chamber 2 has the partcorresponding to the heater 3 described later, which is formed ofmaterials capable of transmitting thermal rays emitting from the heater,at least. The part corresponding to the heater 3 of the chamber 2 isformed of quartz, for example. The chamber 2 is provided with a supporttable 6 for supporting the wafer 5.

[0021] The above heater 3 is provided outside the chamber 2. The heater3 heats the wafer 5 housed in the chamber 2. The heater 3 is composed ofseveral heating lamps 7. The heating lamps 7 are arranged so as tosimultaneously heat both (front and back) principal surfaces of thewafer 5 housed in the chamber 2. The heating lamps 7 may be xenon lampsor tungsten halogen lamps. By doing so, it is possible to heat the film34 by heating method calling RTA (Rapid Thermal Anneal) or RTP (RapidThermal Process). In other words, the film 34 can be effectively heatedfor short time.

[0022] The adsorbent 4 is provided in the chamber 2 so that it can befreely taken in and out (removable) in order to adsorb the volatilemetal compound generated from the film 34 included in the wafer 5 whenheating the wafer 5. The adsorbent 4 adsorbs the volatile metal compoundgenerated from the film 34. The volatile metal compound can thereby beprevented from adhering to the surface of the film 34. Morespecifically, the volatile metal compound adheres to the surface of thefilm 34. As a result, no crystal particles (abnormal particles)containing metal element of the volatile metal compound will begenerated on the surface of the film 34. Thus, the adsorbent 4 may bealso called an inhibitor. The adsorbent 4 is previously provided in thechamber at least before the film 34 (i.e., wafer 5) is heated. Thecrystal particles in the chamber 2 are used as the adsorbent 4, usingthe volatile metal compound generating from the film 34 as material. Theadsorbent 4 remains in the chamber 2 in the method described in thefollowing.

[0023] Before the wafer 5 (film 34) is heated, a dummy substrate (dummywafer) 8 having the same quality film 34 as the film 34 of the wafer 5is heated in the chamber 2. In this case, the dummy wafer 8 is heated inthe same atmosphere as in the actual heating treatment of the wafer 5.By doing so, the gaseous volatile metal compounds are generated from thefilm 34 of the dummy wafer 8 so that it can adhere to an inner wallsurface of the chamber 2.

[0024] The volatile metal compound adheres to the inner wall surface ofthe chamber 2, and thereafter, is decomposed into a gas component and asolid component containing metal elements of the volatile metalcompound. The solid component grows as crystal particles 4 in a state ofadhering to the inner wall surfaces of the chamber 2, and then, remainson the inner wall surface of the chamber 2. The above-mentioneddecomposition reaction is reversible. However, a reverse reaction ishard to occur. In other words, any component is hard to gasify once itis a crystallized (solidified). Therefore, the crystal particles 4,adhering to the inner wall surface of the chamber 2 are hard to revertto the volatile metal compound. In addition, the volatile metal compoundcan be easily adsorbed to the crystal particles 4 containing the samemetal element. For this reason, when the crystal particles 4 is oncegenerated, the volatile metal compounds generating from the film 34 arealmost adsorbed to the crystal particles 4. Since the volatile metalcompounds adsorbed to the crystal particles 4 cause the decompositionreaction and crystal growth on the crystal particles 4, new crystalparticles 4 are formed.

[0025] As described above, the decomposition reaction and crystal growthcontinuously occur while the volatile metal compounds are generated fromthe film 34. Similarly, the same reaction as described above occurswhile the volatile metal compounds are generated from the film 34 whenheating the wafer 5. That is, once the crystal particles 4 are formed atportions other than the wafer 5 (film 34), most of the volatile metalcompounds to be generated later from the film 34 is consumed as thematerial for crystal particles 4 growing at the portions other than thewafer 5. Therefore, even if the wafer 5 is repeatedly heated in thechamber 2, there is almost no possibility that the volatile metalcompounds are filled or saturated in the chamber 2. In addition, thereis almost no possibility that the crystal particles 4 grow in the abovereversible reaction (decomposition reaction) at the portions other thanthe inner wall surface of the chamber 2. In the manner described above,the volatile metal compound generating from the film 34 can be preventedfrom adhering to the surface of the film 34 when the wafer 5 is heated.As a result, it is possible to prevent the crystal particles 4containing metal element of the volatile metal compound can be preventedfrom being generated on the surface of the film 34.

[0026] The dummy wafer 8 is heated until the crystal particles 4adhering to the inner wall surface often chamber 2 reaches apredetermined amount. More specifically, the predetermined amount canadsorb and crystallize the volatile metal compounds generated from eachfilm 34 of the desired number of processed wafers 5. Of course, thepredetermined amount previously includes, the crystal particles 4 whichhave been generated from the volatile metal compound made from the film34 on each wafer 5 and which function as adsorbent. If the amount of thecrystal particles 4 used as adsorbent is smaller than the predeterminedamount when only one dummy wafer 8 is heated, several dummy wafers 8 maybe heated until the amount of the crystal particles 4 reaches thepredetermined amount. As described above, metal compound (crystalparticles) 4 are used as adsorbent 4. The metal compound contains metalelement, which is a component of the volatile metal compound generatedfrom the film 34 of the wafer 5, and is generated from the volatilemetal compound. The detailed component of the above film 34, thevolatile metal compound and adsorbent 4, and the chemical reactiontaking place in the chamber 2 when the wafer 5 and the dummy wafer 8 areheated will be described, in conjunction with the following method ofmanufacturing a semiconductor device.

[0027] The method of manufacturing a semiconductor device according toone embodiment of the present invention will be described with referenceto FIG. 1 to FIG. 3. FIG. 2A to FIG. 2C are cross-sectional viewsshowing the processes in the method of manufacturing a semiconductordevice according to the present embodiment. FIG. 3 is a diagram plottingthe relationship between the number of particles generated when heatingwafer and the number of processed wafers.

[0028] The method of manufacturing a semiconductor device according tothe present embodiment relates to an annealing process using theannealer 1 described before. In particular, the method of the presentinvention relates to an annealing process when forming part of acapacitor device electrode having COP type FeRAM memory cell using metaloxide conductor. Tungsten (W) is used as material for forming a contactplug positioned below capacitor device. A lamination film comprising athin silicon carbide (SiC) film and a thin titanium (Ti) film isinterposed between the contact plug and iridium (Ir) film forming partof the lower electrode of capacitor device.

[0029] As illustrated in FIG. 2A, shallow trench isolation 10 is formedon the surface layer of a P-type Si substrate main body 9. The shallowtrench isolation 10 is formed, burying a SiO₂ layer in an isolationtrench (not shown) formed at the surface layer of the substrate mainbody 9. The isolation trench is formed at regions other than transistoractive regions formed on the surface layer of the substrate main body 9.Hereinafter, the substrate main body 9 provided with capacitor device 28and various electronic devices described later is referred to asprocessing substrate (wafer) 5.

[0030] A transistor 12 for making a switch operation is formed on thesurface layer of the substrate main body 9. An oxide film 13 of, forexample, SiO₂ is formed on the entire surface of the substrate main body9 by hot oxidation until it has a film thickness of about 6 nm. Anarsenic (As)-doped n+ type polycrystalline silicon film 14 is formed onthe entire surface of the SiO₂ film 13. A WSi_(X) film 15 and a nitridefilm 16 such as SiN are further formed on the surface of thepolycrystalline silicon film 14. The polycrystalline silicon film 14,WSi_(X) film 15 and SiN nitride film 16 are processed by normalphotolithography and RIE. A gate electrode 17 is thereby formed on thesurface of the substrate main body 9. A nitride film 18 such as SiN isdeposited on the surface of the substrate main body 9 and covers thegate electrode 17. Thereafter, the SiN film 18 is processed by RIE,i.e., normal process of leaving sidewalls. The sidewall of the gateelectrode 17 is therefore provided with a spacer 18. A source/drainregion 19 is formed on the surface layer of the substrate main body 9 bynormal ion implantation and thermal treatment, which is not describedhere. As a result, the transistor 12 is formed on the surface layer ofthe substrate main body 9.

[0031] As seen from FIG. 2B, contact plugs 20 and 21 are formed on thesurface of the substrate main body 9 having the transistor 12, in thefollowing manner. First, an oxide film (d-TEOS film) such as SiO₂ isdeposited on the entire surface of the substrate main body 9 by CVDprocess so as to cover the transistor 12. Thereafter, the surface of thed-TEOS film 22 is temporarily planarized by CMP process. A contact hole(not shown) through the d-TEOS film 22 is made, exposing one surface ofthe source/drain region 19 exposed. A thin titanium (Ti) film isdeposited in the contact hole and on the surface of the d-TEOS film 22by sputtering or CVD. Thereafter, the Ti film 23 is heated in apredetermined forming gas, forming a TiN film 23 can be formed. Tungsten(W) 24 is deposited on the entire surface of the TiN film 23 by CVD.Thereafter, CMP is performed, removing extra TiN film 23 and tungsten 24from the surface of the d-TEOS film 22. The TiN film 23 and tungsten 24is therefore buried in the contact hole. Thus, one contact plug 20electrically connected to one of the source/drain region 19 is formed.

[0032] A nitride film 25 such as SiN is deposited on the entire surfaceof the d-TEOS film 22 formed with the contact plug 20 by CVD.Thereafter, the other contact plug 21 electrically connected to theother of the source/drain region 19 is formed according to the samemethod as forming the above contact plug 20. First, a contact hole (notshown) is made in the SiN film 25 and the d-TEOS film 22, exposing theother surface of the source/drain region 19. A thin TiN film 26 isformed in the contact hole and on the surface of the SiN film 25.Tungsten (W) 27 is deposited on the entire surface of the TiN film 26.Thereafter, CMP is performed, burying the TiN film 26 and tungsten 27are buried in the contact hole. Another contact plug 21 electricallyconnected to the other of the source/drain region 19 is thereby formed.The contact plug 21 thus formed is electrically connected to capacitordevice 28, which will be described later.

[0033] As depicted in FIG. 2C, a capacitor device 28 is formed on theSiN film 25 having the contact plug 21. Before forming the capacitordevice 28, a front-end layer 29 of the capacitor device 28 is formed onthe surface of the contact plug 21 and the SiN film 25, in the followingmanner. First, a silicon carbide film (SiC) 30 is deposited bysputtering, on the entire surface of the SiN film 25 until it has a filmthickness of about 10 nm. Further, a titanium (Ti) film 31 is depositedby sputtering, on the entire surface of the SiC film 30 until it has afilm thickness of about 3 nm. The front-end layer 29 of the capacitordevice 28 comprising the lamination film of SiC film 30 and Ti film 31is thereby formed.

[0034] The lower electrode 28 a of the capacitor device 28 is formed onthe surface of the Ti film 31 in the following manner. First, an iridium(Ir) film 32 is deposited by sputtering, on the entire surface of the Tifilm 31 until it has a film thickness of about 30 nm. Similarly, a firstplatinum (Pt) film 33 is deposited by sputtering, on the entire surfaceof the Ir film 32 until it has a film thickness of about 20 nm. Further,a metal oxide film, that is, first SrRuO₃ (SRO) film 34 is formed bysputtering, on the surface of the Pt film 33 until it has a filmthickness of about 10 nm. The first SRO film 34 is a portion (film)contacting with a capacitor insulating film 28 b described later of thecapacitor electrode 28 a. In this case, the SRO film 34 is formed withina temperature range from room temperature to about 600° C.

[0035] In order to develop electric conductivity in the SRO film 34, theSRO film 34 is crystallized. More specifically, the chamber 2 of theannealer 1 is filled with oxygen (O₂). The SRO film 34 is heated withina temperature range from about 550 to 650° C. The SRO film 34 istherefore crystallized. The crystallization will be described in detail.

[0036] One component of the SRO film 34, or, Ru (ruthenium), is easy togenerate the volatile metal compound, i.e., RuO₄ in heating process. TheRuO₄ generates RuO_(X) crystal particles (abnormal particles) afterdecomposed on the SRO film 34, as in the conventional technique. Morespecifically, a chemical reaction expressed by the following chemicalformula occurs on the surface of the SRO film 34 based on RuO₄ generatedfrom the SRO film 34.

RuO₄←→RuO₂+O₂

[0037] The RuO₂ crystal particles have a diameter of about 0.5 μm ormore even if they are small. For this reason, it is almost impossible toremove the RuO₂ crystal particles generated on the surface SRO film 34can hardly be removed from there by after-cleaning process. The RuO₂crystal particles on the surface SRO film 34 may cause the operationfailure of the capacitor device 28. In addition, the RuO₂ crystalparticles may degrade the performance, quality, and reliability of thesemiconductor device. Consequently, the yield of the semiconductordevice will decrease, and the manufacturing cost of the semiconductordevice will increase.

[0038] As seen from the chemical formula, the decomposition reaction ofRuO₄ is a reversible reaction. However, the reverse reaction of thedecomposition reaction, that is, the formation reaction of RuO₄ is hardto occur. In other words, the RuO₂ crystal particles are hard to revertto RuO₄. The RuO₄ is easy to be adsorbed to the RuO₂ crystal particlescontaining Ru. Thus, if the RuO₂ crystal particles exist in theatmosphere (reaction system) where the above reversible reaction occurs,the RuO₄ is mostly adsorbed to the RuO₂ crystal particles. The RuO₄adsorbed to the RuO₂ crystal particles make the above decompositionreaction and crystal growth on the RuO₂ crystal particles; as a result,it becomes new RuO₂ crystal particles. The decomposition reaction andcrystal growth continuously takes place while the RuO₄ is generated.Namely, if the RuO₂ crystal particles exist on portions other than thewafer 5 (SRO film 34), the RuO₄ can be prevented from adhering to thesurface of the SRO film 34. As a result, the RuO₂ crystal particles canbe prevented from being generated on the surface of the SRO film 34.Therefore, in the heating process of the SRO film 34, the aboveproperties of RuO₄ and RuO₂ are used, and thereby, the RuO₂ crystalparticles can be prevented from being generated on the surface of theSRO film 34.

[0039] More specifically, as shown in FIG. 1, before the wafer 5, whichwill be product, is heated, the dummy wafer 8 provided with the SRO film34 is heated in the chamber 2 in the same manner as the wafer 5. In thiscase, oxygen is previously supplied into the chamber 2, and then, thedummy wafer 8 is heated at the temperature of about 500° C. That is,before the wafer 5 is actually heated, the dummy wafer 8 is heated undersubstantially the same oxygen atmosphere as heating to the wafer 5. RuO₄is thereby generated from the SRO film 34 of the dummy wafer 8 and canadhere to the inner wall surface of the chamber 2. The RuO₄ adhering tothe inner wall surface of the chamber 2 is decomposed into RuO₂ and O₂.The RuO₄ grows as crystal particle in a state of adhering to the innerwall surface of the chamber 2, and thereafter, remains on the inner wallsurface of the chamber 2. By doing so, RuO₂ crystal particles used asadsorbent 4 is provided on the inner wall surface of the chamber 2.

[0040] Heating to the dummy wafer 8 ends after the amount of the RuO₄crystal particles adhering to the inner wall surface of the chamber 2reaches the amount capable of mostly adsorbing and crystallizing RuO4generated from the SRO films of the desired number of wafers 5. In otherwords, the supply of the RuO₂ crystal particles 4 used as adsorbent tothe inside of the chamber 2 is completed. Thereafter, in the process ofheating the wafer 5, the RuO₄ generated from the SRO film 34 is adsorbedto the RuO₂ crystal particles 4, and thereby, the RuO₄ can be preventedfrom adhering to the surface of the SRO film 34 of the wafer 5. Inaddition, the RuO₂ crystal particles can be prevented from beinggenerated in the chamber 2. As a result, the RuO₂ crystal particles(abnormal particles) can be prevented from being generated on thesurface of SRO film 34 of the wafer 5.

[0041] Here, the experiment conducted by the present inventors will bedescribed below with reference to FIG. 3. The present inventors heatedthe dummy wafer 8 provided with the SRO film 34 in the chamber 2, andthereafter, investigated the relationship between the number ofprocessed wafers and the number of RuO₂ crystal particles generated onthe surface of the SRO film 34. FIG. 3 is a diagram plotting therelationship between the number of RuO₂ crystal particles generated whenheating the dummy wafer 8 and the number of processed dummy wafers 8. Inthis case, only RuO₂ crystal particles having grain size larger than 10μm or more was counted. As is evident from FIG. 3, according to theexperiment conducted by the present inventors, with the increase of thenumber of processed dummy wafers 8, the number of generated RuO₂ crystalparticles decreased. According to the conventional annealing carried outby the present inventors, about 10 RuO₂ crystal particles per waferconstantly adhered to the surface of the SRO film 34. According to theannealing process of the embodiment, it was found that the number ofRuO₂ crystal particles adhered onto the surface of the SRO film 34 wasreduced to about one or two per wafer. Therefore, according to theannealing process of the embodiment, it was found that the generatednumber of RuO₂ crystal particles could be greatly reduced. Namely, itwas found that the number of RuO₂ crystal particles adhering to thewafer could greatly be reduced.

[0042] After the predetermined amount of RuO₂ crystal particles adhereto the inner wall surface of the chamber 2, heating to the wafer 5 isstarted. By doing so, the SRO film 34 of the wafer 5 is crystallized ina proper and clean state and has electric conductivity. Thus, thecapacitor electrode 28 a comprising the lamination film of the above Irfilm 32, Pt film 33 and first SRO film (SRO electrode) 34 is formed onthe front-end layer 29 comprising the lamination film of the above SiCfilm 30 and Ti film 31. Almost no RuO₂ crystal particles adhere to thesurface of the crystallized first SRO film 34, so that clean state isgiven. Therefore, the SRO film 34 would not reduce electricalcharacteristics of the insulating film 28 b of the capacitor device 28formed contacting with the surface. In addition, the electricalcharacteristics of the interface between the SRO film 34 and thecapacitor insulating film 28 b are scarcely degraded. Namely, this meansthat the first SRO film 34 is good quality as the constituent componentof the capacitor lower electrode 28 a. Consequently, the capacitor lowerelectrode 28 a having the above first SRO film 34 is also good quality.

[0043] In this case, rapid thermal annealing (RTA) is performed tocrystallize the first SRO film 34. By doing so, it is possible to reducedamages by heat given to the first SRO film 34.

[0044] The capacitor insulating film (capacitor ferroelectric film) 28b, that is, PZT film (Pb—Zr—Ti—O film) is formed on the surface of thefirst SRO film 34 by sputtering. The PZT film 28 b is temporallysubjected to RTA under the oxygen atmosphere, and thereby, the PZT film28 b is crystallized. The PZT film 28 b is crystallized by using theannealer 1.

[0045] An upper electrode 28 c of the capacitor electrode 28 is formedon the surface of the PZT film 28 b, in the following manner. First, asecond SRO film 35 having a thickness of about 10 nm is formed on thesurface of the PZT film 28 b according to the same method as forming thefirst SRO film 34. The second SRO film 35 is a portion (film) contactingwith the capacitor insulating film 28 b of the capacitor upper electrode28 c. In this case, heating for crystallizing the second SRO film 35 iscarried out using the annealer 1. In the heating process, RTA isemployed. This reduces damages by heat given to the second SRO film 35.

[0046] The amount of RuO₂ crystal particle 4 adheres to the inner wallsurface of the chamber 2 before heating the first SRO film 34. Ofcourse, the amount includes an amount enough to mostly adsorb andcrystallize RuO₄ generated from the second SRO film 35 of the desirednumber of wafers 5. However, in the actual heating process of the secondSRO film 35, the RuO₂ crystal particles 4 previously adhering to theinner wall surface of the chamber 2 and RuO₂ particles, which are newcrystal particles 4 generated in the heating process of the first SROfilm 34, function as the adsorbent 4. Therefore, the amount of the RuO₂crystal particle 4 previously adhering to the inner wall surface of thechamber 2 before heating the first SRO film 34 is set as follows. Thatis, the amount of RuO₂ crystal particle 4 is sufficient so long as itcan mostly adsorb and crystallize RuO₄ generated from the first SRO film34 of the desired number of wafers 5.

[0047] A second platinum (Pt) film 36 is formed by sputtering, on theSRO film 35. The capacitor upper electrode 28 c comprising laminationfilm of the second SRO film (SRO electrode) 35 and the second PT film 36is thereby formed on the surface of the PZT film 28 b.

[0048] Thereafter, oxide film (SiO₂ film) (not shown) is temporallydeposited as processing mask material on the surface of the SiN film 25by CVD process to cover the front-end layer 29, capacitor lowerelectrode 28 a, capacitor ferroelectric film 28 b and capacitor upperelectrode 28 c. The SiO₂ film is patterned while photo resist film (notshown) being removed by normal photolithography and RIE. Thereafter, thesecond Pt film 36, second SRO film 35, PZT film 28 b and first SRO film34 are shaped after being etched by RIE. The above first Pt film 33, Irfilm 32, Ti film 31 and SiC film 30 are shaped after being successivelypatterned by photolithography and RIE processes. The process is carriedout, and thereby, the capacitor device 28 having the desired size andshape can be formed on the front-end layer 29.

[0049] As illustrated in FIG. 2C, an oxide film (d-TEOS film) 37 such asSiO₂ is deposited on the surface of the SiN film 25 by CVD to cover thecapacitor device 28. Under oxygen atmosphere, the d-TEOS film 37 isheated at about 600° C. This serves to reduce damages given to the PZTfilm 28 b in the above-mentioned processing and shaping. When theheating process is completed, the process of forming the capacitordevice 28 ends. In this case, too, the heating process is performed bythe annealer 1.

[0050] In the heating process, the oxygen permeates through thecapacitor device 28 contribute to the recovery of damages to the PZTfilm 28 b. Further, part of oxygen permeates through the capacitor lowerelectrode 28 a. On the other hand, the Ir film 32 has oxygen diffusioninhibitory effect in some degree by itself. In addition, the laminationfilm (front-end layer) 29 comprising the Ti film 31 and SiO film 30 hasdiffusion barrier properties. Thus, there is almost no possibility thatthe contact plug 21 provided below the capacitor device 28 is oxidized.The lamination film 29 comprising the Ti film 31 and SiO film 30 hardlyreacts with the Ir film 32, first Pt film 33 or tungsten plug 21.Therefore, the heating process and each heating process in the oxygenatmosphere, in the manufacturing process of the capacitor device 28,scarcely cause hindrance to the capacitor device 28.

[0051] Thereafter, a desired COP type FeRAM is formed via the followingprocesses, although illustration and details are omitted. Among theprocesses are: a process of forming a contact plug connected to theupper electrode of the capacitor device 28, a process of forming drivelines and bit lines, and a process of forming upper-layer metalinterconnects. Thus, the process of manufacturing the semiconductordevice according to the embodiment ends.

[0052] As described above, according to one embodiment, in the heatingprocess for crystallizing the first and second SRO films 34 and 35, itis possible to prevent RuO₄ from being generated from each of the SROfilms 34 and 35. In addition, RuO₂ crystal particles (abnormalparticles) generated from RuO₄ can be prevented from occurring on eachsurface of the SRO films 34 and 35. Namely, the SRO films 34 and 35 havea clean surface having almost no unnecessary adherent substances(impurities); therefore, good-quality thin SRO films 34 and 35 can bestably formed.

[0053] With the increase of the number of processing times of wafer 5,the amount of RuO₂ crystal particles adhering to the inner wall surfaceof the chamber 2 increases. In other words, with the increase of thenumber of processing times of wafer 5, the amount of adsorbent(inhibitor) 4 increases. Therefore, with the increase of the number ofprocessing times of wafer 5, each surface of the first and second SROfilms 34 and 35 becomes clean. As a result, with the increase of thenumber of processing times of wafer 5, good-quality thin SRO films 34and 35 can be stably formed.

[0054] In the FeRAM using ferroelectric film as the capacitor insulatingfilm, a material hard to reduce electrical characteristics of thecapacitor ferroelectric film is usually used as the portion contactingthe capacitor ferroelectric film of the capacitor electrode. By doingso, the reliability of the capacitor device can be secured. For example,if one of metal oxide ferroelectric films, that is, PZT film is used asthe capacitor ferroelectric film, it is general to use the SRO film asthe portion contacting the PZT film of the capacitor electrode. Asdescribed above, according to the present embodiment, good-quality thinSRO films 34 and 35 is stably formed; therefore, it is possible toprevent the reduction of electrical characteristics of the PZT film 28 band the operation failure of the capacitor device 28. As a result, it ispossible to improve performance, quality and reliability of the COP typeFeRAM that has the capacitor device 28. In addition, it is possible toimprove the FeRAM yield, and to reduce the manufacturing cost of theFeRAM.

[0055] The annealer 1 is used in all heating processes of crystallizingthe PZT film 28 b, and thereby, it is possible to simplify and fastperform the process of manufacturing the above COP type FeRAM. Inaddition, the FeRAM manufacturing system including the annealer 1 can besimplified. It is therefore possible to improve production efficiency ofFeRAM, and to reduce the manufacturing cost thereof.

[0056] The apparatus and method for manufacturing a semiconductor deviceaccording to the present invention is not limited to the above-mentionedembodiment. Various modifications of the constitution or part ofprocesses may be made without departing from the scope of the inventiveconcept, or various setups may be properly combined.

[0057] For instance, in the front-end layer 29 of the capacitor device28, the Ti film 31 is formed on the SiO film 30; however, the filmformed on SiO film 30 is not limited to the Ti film 31. In place of theTi film 31, for example, Zr, Hf, V, Nb or Ta films may be formed on theSiO film 30. In other words, the portion contacting with the capacitorlower electrode 28 a of the front-end layer 29 may be formed ofmaterials containing metal elements of at least one kind of groups IV-Band V-B.

[0058] The PZT film is sued as the capacitor ferroelectric film 28 b;however, the ferroelectric film is not limited to the PZT film. In placeof the PZT film, for example, an Sr—Bi—Ta—O film (SBT film) may be usedas the same ferroelectric film. The crystallization temperature of theSBT film is higher than that of the PZT film. For this reason, in orderto properly form the STB film, heating at a temperature higher than thePZT film is required. However, according to the present invention, thesame effect as the case of employing the PZT film can be obtained.

[0059] Besides, Ba—Sr—Ti—O film (BST film) and Sr—Ti—O film (STO film)containing alkaline earth metal elements such as Ba and Sr may be suedas the above capacitor ferroelectric film 28 b. the above PZT, SBT, BSTand STO are ferroelectric films having a so-called perovskite-typecrystal structure. If the ferroelectric films having so-calledperovskite-type crystal structure are used as ferroelectric film, atleast one metal element forming the A site is used, which is selectedfrom groups II-A, III-B and IV-A as metal element forming the A site.Similarly, if the ferroelectric films having so-called perovskite-typecrystal structure are used as ferroelectric film, at least one metalelement forming the B site is used, which is selected from groups IV-Band V-B as metal element forming the B site. For example, Zr, La, Nb orSn is given in addition to the above metal elements. Pb—Ti—O (PT film),BaTiO₃, PbZnO₃, Ta₂O₅ or Bi₄Ti₃O₁₂ films may be used as the abovecapacitor ferroelectric film 28 b.

[0060] The capacitor ferroelectric film 28 b is not limited toferroelectric films. Normal dielectric films may be used.

[0061] The heating process for crystallizing the first and second SROfilms 34 and 35 is not limited to the temperature range from about 550to 650° C. described before. According to the experiment conducted bythe present inventors, it was found that the same particles inhibitoryeffect as the heating process at the above temperature range wasobtained in the heating process at the temperature range from about 450to 700° C. obtained.

[0062] The first and second Pt films 33 and 36 are used as part of thecapacitor lower and upper electrodes 28a and 28 c; however, thecapacitor electrode is not limited to the above Pt films 33 and 36. Inplace of the Pt films 33 and 36, for example, single metal films such asIr film and Ru film may be used. In addition, conductor films comprisingof metal compound (metal oxide) such as strontium ruthenium oxide may beused. Namely, in the capacitor lower and upper electrodes 28 a and 28 c,the portion provided with the Pt films 33 and 36 may be formed ofmaterials containing metal elements included in at least one kind ofgroups II-A and VIII.

[0063] The first and second SRO films 34 and 35 are used as the portion(film) contacting with the capacitor insulating film 28 b of thecapacitor lower and upper electrodes 28 a and 28 c; however, thecontacting portion is not limited to the SRO films 34 and 35. Inaddition to the above SRO films 34 and 35, the following film may beused. That is, the film is formed of materials containing predeterminednoble metal elements having the volatile metal compound component ormetal elements having high melting point. More specifically, in place ofthe SRO films 34 and 35, the film may be formed of material containingat least one metal element selected from groups II-A, IV-B, VII-B, VIIIand I-B. For example, the film may be formed of material containing atleast one metal element of Ru, sr, Ti, Pt, Re, Ir, Os, Pd, Rh and Au.

[0064] The experiment conducted by the present inventors showed that thesame effect as the SRO films 34 and 35 was obtained even if the filmformed of material containing at least one of the metal elements givenabove was used in place of the SRO films 34 and 35. Further, it wasfound that the film used in place of the SRO films 34 and 35 couldobtain the same effect as the SRO films 34 and 35 so long as the filmcontains at least one of the metal elements given above even if it isformed of a single metal. Further, if the film used in place of the SROfilms 34 and 35 was formed of metal compound conductor, it was foundthat the metal compound should be metal oxide.

[0065] The adsorbent 4 supplied into the chamber 2 is not limited to theRuO₂ described before. The adsorbent 4 may contain at least one of themetal elements given above contained in the portion contacting with thecapacitor insulating film 28 b of the capacitor lower and upperelectrodes 28 a and 28 c. The experiment conducted by the presentinventors confirmed that the same effect was obtained even if theadsorbent 4 was either single metal or metal compound. If the adsorbent4 was metal compound, it was confirmed that the metal compound should bemetal oxide. Further, according to the experiment conducted by thepresent inventors, it was confirmed that the adsorbent 4 might containat least one metal element of IV-B in addition to the metal elementsgiven above. For example, Ti is given as the metal element. In eithercase, the adsorbent 4 supplied into the chamber 2 may be any other formsso long as it can develop the same action and effect as the adsorbent 4.

[0066] The method of providing (supplying) the adsorbent 4 in thechamber 2 is not limited to the process of heating the dummy wafer 8.For example, heating to the dummy wafer 8 has no need to be carried outunder the same atmosphere as actual heating to wafer 5 so long as theadsorbent is obtained. Another method of providing the adsorbent 4 inthe chamber 2 may be performed, in which the adsorbent 4 is directlycoated onto the inner wall surface of the chamber 2. Further, theadsorbent 4 may adhere to the inner wall surface of the chamber 2 bysputtering and CVD processes. Further, the gaseous volatile metalcompound is supplied into the chamber 2 so that the volatile metalcompound can adhere to the inner wall surface of the chamber 2,thereafter, the metal compound may be crystallized as the adsorbent 4.

[0067] The place provided with the adsorbent 4 is not limited to theinner wall surface of the chamber 2. For example, the adsorbent 4 mayadhere to the support table 6. Further, the chamber 2 is provided withan adsorbent holder (not shown), and thereby, the adsorbent 4 may beheld onto the adsorbent holder. In addition, the adsorbent 4 adheres tothe inner wall surface of the chamber 2, the heater 3 does not properlyheat the wafer 5. In this case, the adsorbent 4 is applied to portionsof the inner wall surface, but not to the part facing the heater 3.

[0068] The adsorbent 4 has no need to be always provided in the chamber2. In this case, the following proper amount of adsorbent 4 is suppliedinto the chamber (processing atmosphere). The proper amount is an amountcapable of adsorbing the volatile metal compounds generated from thefilm 34 and 35 when heating the portions (films) 34 and 35 contactingwith the capacitor insulating film 28 b between the upper and lowercapacitor electrodes 28 c and 28 a. That is, when heating the filmcontaining metal elements having the volatile metal compound component,the proper amount of adsorbent capable of adsorbing the volatile metalcompounds generated from the film is supplied into the chamber 2.

[0069] With the increase of the number of processing times of wafers 5,the amount of RuO₂ crystal particle 4 adhering to the inner wall surfaceof the chamber 2 increases. In other words, with the increase of thenumber of processing times of wafers 5, the amount of adsorbent(inhibitor) 4 in the chamber 2 increases. Therefore, with the increaseof the number of processing times of wafers 5, each surface of the firstand second SRO films 34 and 35 becomes cleaner. In other words, with theincrease of the number of processing times of wafers 5, high-qualitythin SRO films 34 and 35 can be stably formed. Consequently, beforeheating to the wafer 5, there is no need of previously providing theamount of adsorbent 4 capable of adsorbing RuO₄ generated from all SROfilms 34 and 35 of the desired number of wafers 5 in the chamber 2.

[0070] The method of providing a large amount of RuO₂ crystal particles4 into the inner wall surface of the chamber 2 is not limited to themethod of heating several dummy wafers 8. For example, the thickness ofthe film 34 provided in one dummy wafer 8 is set thicker than thatprovided in wafer 5. In this case, the film thickness is set so that theamount of RuO₂ crystal particle 4 adhering to the inner wall surface ofthe chamber 2 reaches the predetermined amount described before byone-time heating to the dummy wafer 8. It is therefore possible toshorten time spent for the process of providing the adsorbent 4 in thechamber 2. This can contribute to improving the productivity ofsemiconductor devices.

[0071] After heating to the desired number of wafers 5 is completed, itis desirable that the chamber 2 is supplied with etching gas capable ofremoving the adsorbent 4 adhered in the chamber 2. In this case, thecomponent, flow rate, temperature and pressure of the etching gas areset to the condition capable of mostly removing the adsorbent 4remaining in the chamber 2. By doing so, the used chamber 2 is cleaned,so that the chamber 2 can be held at a clean state as non-used. Inaddition, the inside of the using chamber 2 can be set to proper andclean conditions. Several processing substrate (wafers) 5 have mutuallydifferent metal compound films 34, and each substrate is continuouslyheated. In this case, the inside of the chamber 2 is cleaned by etchinggas every when heating to each substrate 5. The film 34 of eachsubstrate 5 can be therefore continuously heated in proper and cleanconditions. The adsorbent 4 is provided so that it can be freely takenin and out (removable). The adsorbent 4 comprising of materialcorresponding to the volatile metal compound to be adsorbed is used. Bydoing so, the adsorbing action and effect of the adsorbent 4 can beeffectively developed with respect to various volatile metal compounds.

[0072] The shape of the capacitor device 28 is not limited to the planetype described before. The capacitor device 28 may be formed into aso-called stack type. More specifically, the capacitor device 28 may beformed into various solid shapes such as so-called cylinder, concave,convex or pedestal types.

[0073] The process of manufacturing the semiconductor device to whichthe present invention is applied is not limited to the portion (film)contacting with the capacitor insulating film 28 b between the capacitorlower and upper electrode 28 a and 28 c. From the same reason asdescribed before, the present invention is applicable to heatingprocesses for various members in which particles will be generated. Inaddition, the semiconductor device formed according to the presentinvention is not limited to the above-mentioned COP type FeRAM. Forexample, DRAM and MRAM having the capacitor insulating film 28 b formedof normal dielectrics can be manufactured according to the presentinvention. Further, the semiconductor device formed according to thepresent invention is not limited to memory type semiconductor devices.For example, CPUs can be of course manufactured according to the presentinvention.

[0074] The above heating process is not limited to RTA (RTP). Aso-called spike anneal may be employed which can carry out heating inshorter time. The apparatus (annealer) 1 for manufacturing thesemiconductor device is not limited to the heater using lamps such asrapid thermal annealer (RTA) (rapid thermal processor (RTP). Theapparatus 1 for manufacturing the semiconductor device may be a furnace,for example. In addition, the apparatus 1 for manufacturing thesemiconductor device may be configured as a heater combining the rapidthermal annealer (RTA). The apparatus 1 for manufacturing thesemiconductor device may be either single wafer processing type or batchprocessing type.

[0075] As described above, the apparatus and method for manufacturingthe semiconductor device according to the present invention is notlimited to the above embodiment. When the processing substrate providedwith film containing metal element having the volatile metal compoundcomponent is heated, the volatile metal compound generated from the filmis prevented from adhering to the surface of the film. Therefore, cleanconductive films can be formed. In addition, the semiconductor deviceaccording to the present invention includes a semiconductor substratehaving the following conductive films. The conductive films containmetal element having the volatile metal compound component. They areformed at a clean state, preventing the volatile metal compound fromadhering to the surface of the films.

[0076] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. An apparatus for manufacturing a semiconductordevice, comprising: a chamber which holds a to-be-processed substratehaving a film containing at least one kind of metal element which willbecome a component of a volatile metal compound; a heater which heatsthe substrate held in the chamber; and an adsorbent which is provided inthe chamber and which adsorbs the volatile metal compound generated fromthe film by heating the substrate.
 2. The apparatus according to claim1, wherein the film is made of the metal element or a metal compoundcontaining the metal element.
 3. The apparatus according to claim 1,wherein the metal element is at least one kind of metal element includedin groups II-A, IV-B, VII-B, VIII and I-B.
 4. The apparatus according toclaim 1, wherein the adsorbent contains the metal element.
 5. Theapparatus according to claim 1, wherein the adsorbent contains at leastone kind of metal element of a group IV-B.
 6. The apparatus according toclaim 1, wherein the adsorbent adheres to an inner wall surface of thechamber.
 7. The apparatus according to claim 3, wherein the metalelement is at least one of Ru, Sr, Ti, Pt, Re, Ir, Os, Pb, Rh and Au. 8.The apparatus according to claim 4, wherein the adsorbent is a metalcompound containing the metal element.
 9. The apparatus according toclaim 5, wherein the adsorbent is Ti.
 10. A method of manufacturing asemiconductor device, comprising: providing an adsorbent in a chamberholding a to-be-processed substrate and heating the substrate, thesubstrate having a film containing at least one kind of metal elementwhich will become a component of volatile a metal compound; and causingthe adsorbent to adsorb the volatile metal compound generated from thefilm by heating the substrate.
 11. The method according to claim 10,wherein a dummy substrate having a film containing the metal element isheated in the chamber, and the adsorbent adheres to an inner wallsurface of the chamber.
 12. The method according to claim 10, whereinthe adsorbent is deposited directly on an inner wall surface of thechamber and adheres thereto.
 13. The method according to claim 10,wherein the adsorbent is applied to an inner wall surface of the chamberby sputtering or CVD.
 14. A semiconductor device comprising: asemiconductor substrate having a film containing at least one kind ofmetal element which will become a component of a volatile metalcompound, the semiconductor substrate having being heated by anapparatus for manufacturing a semiconductor device, the apparatuscomprising: a chamber which holds the semiconductor substrate; a heaterwhich heats the semiconductor substrate held in the chamber; and anadsorbent which is provided in the chamber and which adsorbs thevolatile metal compound generated from the film by heating thesemiconductor substrate.
 15. The device according to claim 14, whereinthe film is made of the metal element or a metal compound containing themetal element.
 16. The device according to claim 14, wherein the metalelement is at least one kind of metal element included in groups II-A,IV-B, VII-B, VIII and I-B.
 17. The device according to claim 14, whereinthe adsorbent contains the metal element.
 18. The device according toclaim 14, wherein the adsorbent contains at least one kind of metalelement of a group IV-B.
 19. The device according to claim 14, whereinthe adsorbent adheres to an inner wall surface of the chamber.
 20. Thedevice according to claim 14, wherein the film contacts a capacitorinsulating film provided in a capacitor electrode of a capacitor device.21. The device according to claim 16, wherein the metal element is atleast one of Ru, Sr, Ti, Pt, Re, Ir, Os, Pb, Rh and Au.
 22. The deviceaccording to claim 17, wherein the adsorbent is metal compoundcontaining the metal element.
 23. The device according to claim 18,wherein the adsorbent is Ti.
 24. The device according to claim 20,wherein the capacitor insulating film is a ferroelectric film.
 25. Asemiconductor device comprising: a semiconductor substrate having a filmcontaining at least one kind of metal element which will become acomponent of a volatile metal compound, the semiconductor substratehaving being heated by a method of manufacturing a semiconductor device,the method comprising: providing an adsorbent in a chamber holding thesemiconductor substrate and heating the semiconductor substrate; andcausing the adsorbent to adsorb the volatile metal compound generatedfrom the film by heating the semiconductor substrate.
 26. The deviceaccording to claim 25, wherein a dummy substrate having a filmcontaining the metal element is heated in the chamber, and the adsorbentadheres to an inner wall surface of the chamber.
 27. The deviceaccording to claim 25, wherein the adsorbent is deposited directly on aninner wall surface of the chamber and adheres thereto.
 28. The deviceaccording to claim 25, wherein the adsorbent is applied to an inner wallsurface of the chamber by sputtering or CVD.
 29. The device according toclaim 25, wherein the film contacts a capacitor insulating film providedin a capacitor electrode of a capacitor device.
 30. The device accordingto claim 29, wherein the capacitor insulating film is a ferroelectricfilm.